Convert Filename to tag - Removing entries from drop down list

Hi, I'm probably missing something obvious but the number of entries in the drop down list for Convert > Filename to tag has become quite long and I'd like to prune the ones that I don't use.

I know the list automatically saves any set up I use, but some have only been used once, to parse non-standard file names.

I've tried selecting an entry in the list and hitting delete but that doesn't work.

Any clues on how to spring clean the list?

Many thanks

Mark

see the right-arrow-button next to the dropdown list. Click on that and a small menu opens that allows you (among others) to remove the current entry or the whole list.

Or you can move up/down the list with the arrow keys, and the highlighted selection can be removed by Shift+Del.